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 DB November 27, 2005 04:04

Solvers

Hi All,

I wish to know the difference between pressure based solver(eg. star-CD) and density based solver(Fluent). As far as I know both of them use finite volume formulation and use spatial and temporal discritisation(usually implicit)and then use pressure correction schemes(SIMPLE,SIMPISO or PISO) to convert non-linear system of algebraic equations to linear system of equation. These equations are then solved iteratively using Conjugate gradient method or multi grid techniques.

DB

 zxaar November 27, 2005 20:05

Re: Solvers

fluent also has pressure based solver which is exactly same as starCCM+ as far as theory is concerned, i am not sure about the implementation differences.

 DB November 28, 2005 18:52

Re: Solvers

StarCCM+ is density based solver, again people say but I dont know what is the difference between density based solver and pressure based solver.

DB

 Hubert Janocha December 6, 2005 09:26

Re: Solvers

StarCD has the quit normal pressure based solver (segregated solver), which has some stability problems at high mach numbers because of density variations (mach < 1). That's NOT a problem of the solver implementation in star. That's the native of the solver-numeric !!!

StarCCM+ has a coupled solver (velocity and pressure), which has some stability advantages concerning high mach numbers (mach < 1). But I think it is still pressure based.

A real solver for compressible flows (mach > 0.3 and possibly > 1) is a density based solver like the "Rieman-Solver". I don't know if FLUENT uses such a solver.

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